Glass on glass downstems and diffusers are typicaly measured from the bottom of the frosted male fitting to the bottom of the downstem and NOT the overall length. ie: the clear piece of tubing. The diameter of the fitting can be measured anywhere on the tapered fitting. 14mil can measure between 12.5 and 14.5 mil. 19mil fittings can measure between 18 and 19mil, sometimes referred to 18.8mil. 14mil is approx 0.5" and 19mil is approx 0.75"

All handblown glass products are unique and vary in size, shape and color as they are hand made.